1. Field of Invention
This invention relates to film gates generally, and specifically to film gates which may be embraced by a movable cassette, which film gates contain tapered guide fingers and arcuate guide fingers to normalize the position of a film strip in the cassette and move it to a preselected focal plane.
2. Prior Art
An automatic information retrieval system has been devised as disclosed in U.S. Pat. No. 4,025,176 for storing information on film strips in cassettes, for calling up a cassette containing desired information, for unspooling the film strip from the cassette until a desired frame is automatically located, and then projecting that frame for visual inspection. To enable the user of this system to load cassette with spooled film strips, without the necessity for adhesively securing a leader to the film in accordance with the usual practice, a special leader pin has been devised. (U.S. Pat. No. 4,027,832) The cassette is particularly disclosed in U.S. Pat. No. 3,804,498.
Without a leader strip, the film strip may be limp, and may not be in the focal plane. If the cassette were moved toward a conventional film gate, the limp film which might not lie precisely in the focal plane would encounter a portion of the film gate and be torn, broken, or scratched. In order to avoid such damage resulting from the use of conventional film gates in the present system, it was necessary to devise a means to avoid damage to the film strip.